JP5000706B2 - Thermally crosslinkable polyorganosiloxane composition particularly useful in the manufacture of electrical cables or wires - Google Patents

Abstract

A polyorganosiloxane composition that can be vulcanized at high temperature to a silicone elastomer, useful in the field of the manufacture of electrical wires or cables having an improved fire performance is provided. The composition includes a semi-reinforcing filler chosen from the group composed of:—calcined kaolin powders, preferably that have undergone a chemical surface treatment;—talc;—calcium carbonate that may or may not have been surface-treated, for example with vinylsilanes, aminosilanes or (reactive or unreactive) silicone oils; and mixtures thereof.

Description

  The present invention relates to a polyorganosiloxane composition that can be made into a silicone elastomer by a high temperature crosslinking treatment, i.e., a crosslinking treatment at a material temperature of about 100-200C or, if necessary, up to 250C. The invention also relates to the use of the composition for producing a refractory wire or electrical cable covering or part of a primary insulator, in particular by extrusion. And finally, the present invention relates to a refractory electric wire or electrical cable produced using the composition.

  The expression “fireproof wire or electrical cable” is intended to define a wire or electrical cable that is required to guarantee a high fire performance, at least with regard to ash aggregation and smoke concentration. The features to be demonstrated by refractory wires or electrical cables have formed legal regulations in many countries and have been rigorously standardized.

  An electric cable is normally comprised with the single core conducting wire using copper or aluminum like well-known technology. Each of these single-core conductive wires is protected by a cover or a primary insulator formed of one or more concentric layers using a silicone elastomer. Around this covering, or these coverings (in the case of multi-core conductors), in particular one or more packaging agents and / or one or more reinforcements using glass fibers and / or mineral fibers A filler is provided. Further, one or more external covers are provided around it. In the case of a multi-core conductor, the packaging agent and / or reinforcing filler is arranged around the single-core conductor (each with its primary insulator) to form a cover common to all single-core conductors. Yes. The silicone elastomer that forms part of the electrical cable is basically a constituent material of the primary insulator, but the ratio is changed so that the packaging agent and / or the reinforcing filler (common in the case of multi-core conductors) is used. A cover) and / or an outer cover.

  The number of concentric layers using the silicone elastomer that forms the covering or primary insulator of each single-core conductor and the wall thickness of each concentric layer are basically for maintaining operation in accordance with the above-mentioned criteria. Depends on the demands imposed on Generally speaking, it is desirable to do so by using one or two concentric layers that are at least about 0.5 mm thick, preferably at least about 0.8 mm thick.

  For example, in France, for fire resistance testing of electrical cables, one important criterion that must be met is the standard NFC32-070CR1, which relates to the operating time of electrical cables that burn under limited conditions. . Fire resistance is based on the amount of ash produced that allows sufficient insulation to be maintained for the operation of electrical cables, which is required to exhibit a particular cohesiveness. In this test, each cable sample is provided in a metal tube, and the metal tube itself is provided in a heating furnace that reaches 920 ° C. in 50 minutes and the temperature is maintained for 15 minutes thereafter. . During this test, the cable samples are regularly impacted (impact is provided by an impact bar that strikes the metal tube twice per minute). The test passes if the control lamp connected to the cable and functioning with a small voltage does not go off at the end of the test (ie after 65 minutes). If at least 80% of the multiple tests pass, the above criteria are satisfied.

Another important criterion for fire resistance testing and which must be met is part 1 and 2 of the international standard IEC 61 034 (IEC is an abbreviation for the International Electrotechnical Commission). The standard relates to a measurement of the concentration of smoke generated by the burning of electrical cables under limited conditions. In this test, light transmission is measured in a small chamber of 27 m ³ volume that is made opaque by smoke generated by burning an electrical cable with an alcohol flame under limited conditions. If the light transmittance is at least 60%, the above criteria are satisfied.

  From the viewpoint of suppressing the spread of fire, each of the above criteria can be satisfied only for electric wires and electric cables whose primary insulator material is a specific research object. In fact, it has been observed by known techniques that primary insulator materials using silicone elastomers obtained by high temperature crosslinking of suitable polyorganosiloxane compositions pass the fire spread inhibition test. When the silicone elastomer burns, it is converted into an ash insulating material with specific cohesive properties, generating white smoke resulting from self-ignition of volatile residues resulting from the decomposition of the elastomer.

In the prior art, polyorganosiloxane compositions that can be cross-linked at high temperatures and converted into silicone elastomers form insulating ash materials with specific cohesive properties in the event of a fire, and cable burn time A polyorganosiloxane polymer that crosslinks with the catalytic action of a peroxide and a flow type and / or a thin plate type extender, which may be present alone, combined with platinum or metal oxide You may do it. What has been described above is the use of ZnO (as a flow agent) and mica (as a lamellar extender) and optionally those combined with platinum and / or metal oxides such as, for example, titanium oxide and Fe ₃ O _4. Proposed EP-A-0 467 800.

As an example of the prior art, WO 01/34696 includes
-100 parts of component a) comprising at least one polyorganosiloxane polymer;
-5 to 80 parts of at least one reinforcing filler;
-0.2 to 8 parts of organic peroxide,
-8-30 parts of mica,
-6 to 20 parts of zinc oxide;
-0-15 parts of at least one additive conventionally used in the field of high temperature crosslinking of polyorganosiloxane compositions;
Including
The composition further includes other essential components as follows:
-0.0010 to 0.02 part of platinum, platinum compound and / or platinum complex,
-2-10 parts of titanium oxide;
-50 to 120 parts of component i) comprising at least one bulking agent;
A polyorganosiloxane composition that can be cross-linked at high temperature and converted to a silicone elastomer is disclosed.

As another composition, WO 01/34705 includes
a) at least one polyorganosiloxane polymer;
b) at least one reinforcing filler;
c) an organic peroxide;
d) with mica,
e) zinc oxide;
f) optionally, at least one additive conventionally used in the field of high temperature crosslinking of polyorganosiloxane compositions;
Including
The composition further includes other essential components as follows:
g) platinum, platinum compounds and / or platinum complexes;
h) titanium oxide;
i) at least one bulking agent;
j) at least one mineral belonging to wollastonites,
A polyorganosiloxane composition is disclosed that can be converted to a silicone elastomer having improved fire resistance by crosslinking at elevated temperatures.

Finally, International Publication No. 2004/064081
a) at least one polyorganosiloxane polymer;
b) at least one reinforcing filler;
c) an organic peroxide;
d) with mica,
e) zinc oxide;
f) optionally, at least one additive conventionally used in the field of high temperature crosslinking of polyorganosiloxane compositions;
g) platinum, platinum compounds and / or platinum complexes;
h) titanium oxide;
i) at least one bulking agent;
j) optionally, at least one mineral belonging to wollastonites,
Including
The extender i) of the composition comprises a surface-treated aluminum hydroxide (Al (OH) ₃ ) powder, characterized in that it can be crosslinked at high temperatures and converted into a silicone elastomer The use of siloxane compositions is disclosed.
International Publication No. 01/34696 Pamphlet International Publication No. 01/34705 Pamphlet International Publication No. 2004/064081 Pamphlet

  However, the polyorganosiloxane compositions that have been proposed so far, which can be cross-linked at high temperatures and converted into silicone elastomers, are not completely satisfactory, especially in terms of their manufacture and use. . Specifically, these compositions have a drawback of having adhesiveness that complicates handling (or processability) during industrial production and extrusion molding in the manufacturing process of electric wires or electric cables. In addition, compromises are still being considered from the standpoints of ceramization, low smoke concentration from electrical cable combustion, mechanical properties before and after aging, and ease of use (or processability) of the product. ing.

Therefore, the object of the present invention is at least the following points;
For all compositions according to the invention, on the one hand, good ash cohesive strength meeting the standard NFC32-070CR1 at 500 volts,
A good ability to maintain a low smoke concentration, which generally achieves the goal of greater than or equal to 80% transmission, in accordance with Part 1 and 2 of IEC 61 034,
The fireproof performance is very high even when simply forming the primary insulator, and it has no harmful adhesiveness like the prior art, and has the ease of processing which is an important advantage in industrial production. It is to produce a polyorganosiloxane composition that can be cross-linked at high temperatures and converted to a silicone elastomer, which can provide electrical wires and electrical cables that can be processed and formed more easily. .

  Another object of the present invention is also to provide improved combustion stability, while at the same time, particularly in IEC 2 cable standards (especially Shore A hardness, tensile strength, dashed line length, both in the unrecovered state and in the recovered state. And in terms of modulus) to provide a polyorganosiloxane composition that crosslinks at high temperatures with good mechanical properties even after 10 days at a temperature of 200 ° C.

  Polyorganosiloxane compositions that can be cross-linked at high temperatures and converted to silicone elastomers have now been discovered, which constitutes the first subject of the present invention and at least the above-mentioned improvements with respect to ash cohesion and smoke concentration. While achieving the good mechanical properties of the silicone elastomer formed, especially in the field of manufacturing electric wires or electrical cables with improved fire resistance compared to when using the prior art Can be used.

More particularly, the invention is in its first subject matter:
a) at least one polyorganosiloxane polymer;
b) at least one reinforcing filler;
c) at least one organic peroxide;
d) with mica,
e) zinc oxide;
f) optionally, at least one additive conventionally used in the field of high temperature crosslinking of polyorganosiloxane compositions;
g) platinum, platinum compounds and / or platinum complexes;
h) titanium oxide;
i) at least one bulking agent;
j) optionally, at least one mineral belonging to wollastonites,
k) at least one semi-reinforcing filler k);
Including
A semi-reinforcing filler k) of the composition
A calcined kaolin powder, preferably a chemically surface-treated calcined kaolin powder,
-Talc,
-Surface treated with, for example, vinyl silane, amino silane or silicon oil (reactive or non-reactive) or unsurfaced calcium carbonate, and
-Can be cross-linked at high temperatures and converted into silicone elastomers, characterized in that they are selected from the group consisting of mixtures thereof, especially in the field of the production of electric wires or electrical cables with improved fire resistance It relates to a polyorganosiloxane composition that can be used.

That is, the applicant has provided an excellent compromise in the use of electrical wires or electrical cables by the use of special semi-reinforcing fillers k) in the composition of the invention,
-Good mechanical properties of the elastomer before and after degradation (10 days at 200 ° C),
-Good ash cohesion,
-Good low smoke density maintenance ability,
-Good extrusion properties, and
-It has been found that it is possible to obtain ease of use (or processability) of the improved composition relative to conventional compositions.

Kaolin is an aluminosilicate composed mostly of the following species: Al ₂ O ₃ .2SiO ₂ .2H ₂ O. The physical properties of kaolin are changed by being treated (calcined) at a high temperature (700 to 1200 ° C.). Firing makes the particles whiter and reduces the hydrophilicity and conductivity of the particles. The chemical surface treatment characteristics of the calcined kaolin are not limited to treatment preferences based on (reactive or non-reactive) silicone oil, vinyl silane or amino silane.

Without limitation, their concentration is about 2.6 and the specific surface area is 8-20 m ² / g. The particle diameter is 0.5 to 1.5 μm.

Thus, the composition according to the invention comprises at least one polyorganosiloxane polymer a) containing 0 to 4% by weight, preferably 0.01 to 3% by weight, of vinyl groups. These polyorganosiloxane polymers a) are 50,000 to 1,000,000 mPa.s at 25 ° C. When it has a viscosity of s, it is called oil, but 1000000 mPa.s. When it exceeds s, it is called rubber. In the composition of the present invention, the polyorganosiloxane polymer is an oil, rubber or mixture. These polyorganosiloxane polymers are linear polymers whose diorganosiloxane chains consist essentially of the group of the chemical formula R ₂ SiO. This chain is terminated at both ends by a group of chemical formulas R ₃ Si _0.5 and / or OR ′ groups. In these chemical formulas:
-R is the same or different and represents the following monovalent hydrocarbon groups. An alkyl group such as methyl, ethyl, propyl, octyl and octadecyl; an allyl group such as phenyl, tolyl and xylyl; an aralkyl group such as benzyl and phenethyl; and a cyclohexyl, cycloheptyl and cyclohexenyl group; A cycloalkyl group and a cycloalkenyl group, for example, an alkenyl group such as a vinyl or allyl group; for example, an alkaryl group and a cyanoalkyl group such as a cyanoethyl group; for example, chloromethyl, 3,3,3-trifluoropropyl, chlorophenyl, Haloalkyl, haloalkenyl and haloallyl groups such as dibromophenyl and trifluoromethylphenyl groups;
-R 'represents a hydrogen atom, an alkyl group containing 1 to 4 carbon atoms, or a β-methoxyethyl group.

Preferably, at least 60% of the R group is a methyl group. However, in the diorganopolysiloxane chain, groups other than R ₂ SiO, for example, RSiO _1.5 and / or SiO ₂ group, may be present in a minute amount so as not to exceed 2% (this% value). Represents the number of groups of T and / or Q per 100 silicone atoms).

Specific examples of the group of chemical formulas R ₂ SiO and RSiO _0.5 and the OR ′ group may be as follows.
(CH ₃ ) ₂ SiO, CH ₃ (CH ₂ ═CH) SiO, CH ₃ (C ₆ H ₅ ) SiO, (C ₆ H ₅ ) ₂ SiO, CH ₃ (C ₂ H ₅ ) SiO, (CH ₃ CH _{2 CH 2) CH 3 SiO,} CH 3 (n-C 3 H 7) SiO, (CH 3) 3 SiO 0.5, (CH 3) 2 (CH 2 = CH) SiO 0.5, CH 3 (C 6 H 5) ₂ SiO _0.5 , CH ₃ (C ₆ H ₅ ) (CH ₂ ═CH) SiO _0.5 ,
_{OH, -OCH 3, -OC 2 H} 5, -O-n-C 3 H 7, -O-iso-C 3 H 7, -O-n-C 4 H 9, -OCH 2 CH 2 OCH 3

  These oils and rubbers are sold as silicone products. Moreover, they may be manufactured by a known technique.

The reinforcing filler b) is composed of pyrogenic silica, precipitated silica or a mixture of the two. The silica that can be used is a bulking agent characterized by a fine particle size, usually a diameter of 0.1 μm or less, and a high ratio of specific surface area to weight, generally in the range of about 50 to 300 m ² / g or more. It consists of This type of silica is a commercially available product and is well known in the silicone rubber industry. These silicas are produced by an exothermic process (so-called exothermic silica or fumed silica) or a wet process (precipitated silica). Further, these silicas may or may not be treated with the organosiloxane composition usually used for this purpose. The chemistry and manufacturing process are not important for the purposes of the present invention provided that they can exert a reinforcing action in the finished elastomer. Of course, various silicas may be cut and used.

  The organic peroxide comprising component c) may be any one of those agents that function as a crosslinking agent for the composition forming the silicone elastomer. Thus, for example, ditertiary butyl peroxide, benzoyl peroxide, monochlorobenzoyl peroxide, 2,4-dichlorobenzoyl peroxide, tertiary butyl peracetate, dicumyl peroxide, 2,5-dimethylhexane-2, Peroxides or peracid esters known to be used with silicone elastomers such as 5-diperbenzoate and 2,5-bis (tertiarybutylperoxy) -2,5-dimethylhexane Any of these may be sufficient. During the production of electrical cables or wires by extrusion, the choice of peroxide is in fact the process employed to recover the elastomer (crosslinking process). When the crosslinking step is carried out, for example, in the presence of pressure using a hot stove and / or (infrared) radiation, the peroxide used is preferably monochlorobenzoyl peroxide and / or 2,4-dichloro. Benzoyl peroxide. When the crosslinking step is performed, for example, in the presence of pressure using a steam tube, the peroxide used is preferably 2,5-bis (tertiarybutylperoxy) -2,5-dimethylhexane. .

  The mica containing component d) of the composition according to the invention may be of the muscovite type or phlogopite type. The particle size of mica is not particularly important as long as it is small enough to uniformly disperse in the components of the composition. The mica is preferably used in the form of powder or powder having a particle diameter of less than 100 μm.

  The zinc oxide containing component e) of the composition according to the invention is a white or slightly yellowish powder.

The platinum of component g) can be a basic platinum group or, in particular, chloroplatinic acid (eg hexachloroplatinic acid H ₂ PtCl ₆ ); or a mixture of platinum and organic products, such as in particular a mixture of platinum and vinyl oraga A compound represented by a chemical formula (PtCl ₂ .olefin) ₂ and H (PtCl ₃ .olefin) (where olefin is ethylene, propylene, butylene, cyclohexene or styrene) And a mixture of platinum chloride and cyclopropane may be formed.

  Titanium oxide h) is a white powder.

  The bulking agent i) is more generally crystalline silica or alumina or a mixture of the two. As alumina, it is advantageous to use alumina having high dispersibility. This alumina may or may not be doped in a known manner. Of course, various aluminas may be cut and used. Without limitation, examples of such alumina may include Baikowski's alumina A125, CR125 and D65CR, or Nabaltec's alumina (eg, AP40VS1).

  Crystalline silica often has a particle size greater than 0.1 μm. The term “crystalline silica” is understood as meaning crushed quartz and diatomaceous earth. Of course, various crystalline silicas may be cut and used. The bulking agent i) is preferably crushed quartz.

The composition of the present invention further contains at least one mineral j) belonging to the wollastonite group as an optional component. The wollastonite group has the following mineral species. Calcium metasilicate (CaSiO ₃ ) or wollastonite; mixed calcium sodium silicate (NaCa ₂ HSi ₃ O ₉ ) or sodium ash needle; and mixed calcium metasilicate manganese [CaMn (SiO ₃ ) ₂ ] or bastam stone. Of course, it is also possible to use mixtures of these various species. If one kind of component j) is used, wollastonite is preferred. Wollastonite exists in two forms. That is, wollastonite itself and pseudo wollastonite or β-CaSiO ₃ that are displayed to chemists as α-CaSiO ₃ and are usually found in a natural state. More preferably, wollastonite α-CaSiO ₃ is used. The mineral species j) belonging to the wollastonite species may be untreated or may be treated with an organosilicone compound of the type described above with respect to the aluminum hydroxide powder.

  In addition to the components a), b), c), d), e), g), h), i) and j) specifically mentioned above, the composition according to the invention is further optionally, for example In particular at least one anti-structured product f1); and / or at least one polysiloxane resin f2); and / or at least one stabilizer f3); and / or dyed wires and And / or one or more auxiliary additives f) such as at least one pigment f4); and / or at least one boron compound f5) for producing electrical cables.

According to a preferred embodiment of the present invention, the composition is a composition that can be cross-linked at high temperature and converted to a silicone elastomer, based on 100 parts by weight of polyorganosiloxane polymer a):
-15 to 100 parts of reinforcing filler b),
-0.2 to 8 parts of organic peroxide c),
-0.5-30 parts of mica d),
-0.2 to 10 parts of zinc oxide e),
-0-15 parts of auxiliary additive f),
-0.005 to 0.02 part by weight (i.e. 5 to 200 ppm) of (basic) component g) represented by the platinum group;
-0.5 to 10 parts of titanium oxide h),
-20 to 100 parts of bulking agent i),
-0-10 parts of one or more species j) belonging to the wollastonite group, and
-1 to 100 parts, preferably 20 to 80 parts, more preferably 40 to 70 parts semi-reinforcing filler k),
Is included.

Returning to auxiliary additive f), when one or more of them are used, more specifically (per 100 parts by weight of polyorganosiloxane polymer), auxiliary additive f) is:
Polydimethylsiloxane oil having a viscosity of 10 to 3000 mPa.s at −25 ° C. and having both ends terminated with hydroxyl groups, and / or having a viscosity of 10 to 1000 mPa.s at 25 ° C. and having both ends terminated with hydroxyl groups 0.1 to 15 parts by weight of an anti-structured product f1) based on poly (methylvinyl) siloxane oil; and / or
Essentially the group R ′ ″ ₃ SiO _0.5 and SiO _4/2 (R ′ ″ is optionally a halogenated monovalent hydrocarbon group of less than 7 carbon atoms, SiO _{4 /} R '' for _{2 '.} the weight ratio of 3 SiO _0.5 is 0.5 / 1 to 1/2/1 resin called MQ composed); essentially HR''' ₂ SiO _0.5 and SiO ₂ M'Q group (R '''is defined as above, HR for SiO _2' weight ratio of '' ₂ SiO _0.5 is 0.5 / 1 to 10/1.) composed of 0.1 to 5 parts of a polysiloxane resin f2) represented by a resin; and / or
-For example, in particular iron octoate or cerium octoate (more specifically 0.01 to 1 part ratio range); cerium oxide, cerium hydroxide or iron oxide (more specifically 0.1 to 4 parts) Part ratio range); oxide CaO, oxide MgO (more specifically 0.01 to 0.4 part ratio range); and the like, stabilization of metal salts of organic acids such as iron and cerium salts 0.01 to 4 parts of agent f3); and / or
-0.01 to 5 parts of colored pigment f4); and / or
-Containing 0.01 to 3 parts of boron compound f5) such as alkyl ester type boric acid having 1 to 3 carbon atoms and derivatives thereof;
-The total amount of additives, when one or more are used, is 15 parts by weight in the case of normally obtained compositions, 12 parts by weight in the case of preferred compositions, and in the case of more preferred compositions 10 parts by weight.

  According to one preferred embodiment of the present invention, a total of 0.1 to 10 parts of cerium hydroxide is present to improve ash aggregation.

  To produce the composition according to the present invention, the various components are intimately mixed using equipment well known in the silicone elastomer industry that can be incorporated in any order.

  In addition, according to the second subject of the present invention, the present invention relates to a polyorganosiloxane composition which is shown in particular for the production of a primary insulation for a covering or single conductor used in the construction of refractory wires or electrical cables. Regarding use.

  According to a third subject, the present invention relates to an electric wire or an electrical cable manufactured using a polyorganosiloxane composition according to the first subject.

  In the context of such use, the compositions of the present invention are deposited around the conductors by standard methods, particularly extrusion methods. The material deposited in this way is then crosslinked by heating to form a primary insulator composed of silicone elastomer. Of course, the heating time depends on the temperature of the material and the working pressure. The temperature of the material is generally in the range of 100-200 ° C. For example, it is possible to deposit two or more layers simultaneously using a connected extrusion line with a crosshead or a coextrusion line.

  The present invention also relates to a polyorganosiloxane composition according to the first subject of the present invention for the production of one or more single conductor coverings or primary insulators used in the construction of refractory wires or electrical cables. With respect to the use of the product, comprising the steps of depositing the composition around each single conductor, and then crosslinking it into a silicone elastomer by heating to a material temperature in the range of 100-200 ° C. ing. The invention also relates to a refractory wire or electrical cable produced by the use of a polyorganosiloxane composition as described above.

  The wire or electrical cable according to the invention is low enough to achieve a light transmission of 80% according to Part 1 of the standard IEC 61 034, and meets the standard NFC 32-070CR1 under a voltage of 500 volts.

  Other features and advantages of the present invention will become more apparent in light of the embodiments pointed out below.

(Example and Comparative Example A)
1. Compositions according to the invention (all parts are given by weight)
1.1 Preparation The following were mixed in a mixer grinder with a Z-shaped blade for 2 hours at room temperature (23 ° C.).
-Contains 120 ppm of vinyl groups and 20 million mPa.s at 25 ° C. polyorganosiloxane a) which has a viscosity of s and is a polydimethylsiloxane terminated at both ends with dimethylvinylsiloxy groups a) 65 parts-containing 720 ppm vinyl groups in the chain and 20 million mPa.s at 25 ° C. having a specific surface area of 35 parts-D ₄ (octamethylcyclotetrasiloxane)-200 m ² / g, which is a polydimethylmethylvinylsiloxane having a viscosity of s and terminated with a trimethylsiloxy group at both ends. Treated pyrogenic silica b) 20 parts-pyrolytic silica having a specific surface area of 150 m ² / g b) 13 parts-containing 9% by weight of hydroxyl groups at 25 ° C. and 50 mPa.s. polydimethylsiloxane oil f1) having a viscosity of s and terminated at both ends by dimethylhydroxysiloxy groups f1) 3 parts-containing 9% by weight of hydroxyl groups, 3% by weight of vinyl groups in the chain, and 25 mPa.s at 25 ° C. polymethylvinylsiloxane oil f1) 2 parts-muscovite mica d) 1.8 parts-zinc oxide e) 5 parts-pyrolytic TiO ₂ h) 2.8 parts-α-CaSiO ₃ (wollastonite) j) 3.5 parts-divinyltetramethyldisiloxane treated with methylalkoxysilane sold by Quartz Werke under the trade name Wollastonite Tremin 283-800 TST In the case of a divinyltetramethyldisiloxane solution of a platinum complex (Karsttedt complex) containing 10% by weight of coordinated platinum, the platinum group g) 0.0025 parts-calcium oxide f3) 0.29 parts-iron octoate f3) 0 .4 parts _{- Ce (OH) 4 f3)} 2 parts - Sifraco, Inc. under the trade name E600 ( Bulking agent which is a ground quartz sold by Li, France) i) Bulking agent which is a calcined kaolin surface-treated with aminosilane sold by Burgess (USA) under the trade name 48.5 parts-B2211 k) 41.6 parts

  Thereafter, the mixture obtained as described above is treated with a two-roll crusher, and an organic peroxide forming catalyst c) is added into the mixture.

1.2 Properties of the composition A portion of the homogenate obtained with the above-mentioned mixer is catalyzed with 1.5 parts of 2,4-dichlorobenzoyl peroxide per 100 parts and then extruded for use in the manufacture of electrical cables. Cut into stripes for installation in the machine. The manufacture of electrical cables produces a 3 mm diameter cable with a 1.38 mm diameter single core copper wire surrounded by a 0.81 mm thick cover or primary insulator formed of silicone elastomer. It has a standard configuration. This is achieved by coating a single-core conductor with the above-described homogeneous polyorganosiloxane composition and performing a crosslinking treatment for 46 seconds in a hot air oven set at a temperature of 250 ° C. (material production temperature is set at 130 to 140 ° C.). can get. The standardized sample is then removed from the cable and evaluated for the following characteristics:
-Ash flocculation at 500 volts according to standard NFC 32-070, and
-Smoke density (permeability%) according to part 1 of the standard IEC 61 034

The homogenate is then processed with a suitable mold at 115 ° C. for 8 minutes to form a 2 mm thick plaque. In this way, plaques are obtained in a non-postcured (NPC) state. Thereafter, a part of the plaque is subjected to aging or post-curing (PC) treatment at 200 ° C. for 10 days. Subsequently, standardized samples for all these plaques are removed and the following properties are evaluated.
-Shore A hardness (H _SA ) according to standard DIN 53505
-Tensile strength (TS) [MPa] according to standard AFNOR NF T 46002
-Broken line length (E / B) according to the above criteria [%]
-Elastic modulus at 100% (E / M) [MPa] according to the above criteria
The obtained results are shown in Table 1 described later.

2. Composition according to Comparative Example 2.1 Preparation The following were mixed in a mixer grinder having a Z-shaped blade at room temperature (23 ° C.) for 2 hours.
-Contains 120 ppm of vinyl groups and 20 million mPa.s at 25 ° C. polyorganosiloxane a) which is a polydimethylsiloxane having a viscosity of s and terminated at both ends with dimethylvinylsiloxy groups a) 66.61 parts-containing 720 ppm of vinyl groups in the chain and 20 million mPa.s at 25 ° C. polyorganosiloxane which is a polydimethylmethylvinylsiloxane having a viscosity of s and terminated at both ends with a trimethylsiloxy group a) having a specific surface area of 33.39 parts-D ₄ (octamethylcyclotetrasiloxane) -200 m ² / g Treated pyrogenic silica b) 19.07 parts-pyrolytic silica having a specific surface area of 150 m ² / g b) 12.4 parts-containing 9% by weight of hydroxyl groups and at 50 ° C. at 25 ° C. . polydimethylsiloxane oil f1) having a viscosity of s and terminated at both ends with dimethylhydroxysiloxy groups f1) 2.86 parts-containing 9% by weight of hydroxyl groups, 3% vinyl groups in the chain, and 25 mPa.s at 25 ° C. Polymethylvinylsiloxane oil f1) having a viscosity of s and terminated at both ends by a methylvinylhydroxysiloxy group f1) 1.91 parts-muscovite mica d) 9.61 parts-zinc oxide e) 4.89 parts-thermal decomposition TiO ₂ h) 3.46 parts-α-CaSiO ₃ (wollastonite) treated with methylalkoxysilane sold by Quartz Werke under the trade name Wollastonite Tremin 283-800 TST j) 6.62 parts-divinyltetra In the case of a divinyltetramethyldisiloxane solution of a platinum complex (Karstedt complex) containing 10% by weight of platinum coordinated to methyldisiloxane, platinum group g) 0.003 parts-calcium oxide f3) 0.28 parts-octo acid Iron f3) 0.39 parts-Ce (OH) ₄ f3) 2.76 parts, and
-Bulking agent i) 66.17 parts aluminum hydroxide treated with 1% by weight of vinyltri (2-methoxyethoxy) silane sold by Nabaltec under the trade name Aluminum hydroxide AP 40 VS1.

  Thereafter, the mixture obtained as described above is treated with a two-roll crusher, and organic peroxide c) is added into the mixture.

The ease of use (or processability) of the mixture is assessed by the two rolls of the grinder. The mixture is evaluated according to the following criteria.
0 = Very sticky to the roll and cannot be processed by the roll.
1-2 = Adhesive and treatment with a roll is difficult.
3-4 = Slightly sticky.
5 = not sticky and the mixture is easily handled by the blade.

2.2 Properties of the composition This property is evaluated as indicated in 1.2 above.

  Thus, it can be seen that the present invention provides desirable compromises regarding processability, ceramization, smoke density, and mechanical properties.

  Further, the mechanical properties of the elastomer according to the present invention before and after aging at 200 ° C. for 10 days are improved by 20 to 30% with respect to the comparative example. In the present invention, the composition before cross-linking is not tacky, whereas in the comparative example, it is tacky. Thus, the composition according to the present invention can be used more easily than the comparative example.

Claims (10)

Crosslinked at high temperature a polyorganosiloxane composition as possible out be converted into a silicone elastomer,
For 100 parts by weight of polyorganosiloxane polymer a):
-15 to 100 parts of reinforcing filler b) excluding mica;
-0.2 to 8 parts of organic peroxide c),
-0.5-30 parts of mica d),
-0.2 to 10 parts of zinc oxide e),
-0-15 parts of auxiliary additive f),
-0.0005 to 0.02 parts by weight (that is, 5 to 200 ppm) of component g) represented by platinum element;
-0.5 to 10 parts of titanium oxide h),
-20 to 100 parts of bulking agent i),
-0-10 parts of one or more species j) belonging to the wollastonite group, and
-1 to 100 parts of semi-reinforcing filler k) ,
Including
A semi-reinforcing filler k) of the composition
-Calcined kaolin powder,
-Talc,
-Calcium carbonate and
A polyorganosiloxane composition, characterized in that it is selected from the group consisting of mixtures thereof. The polyorganosiloxane composition according to claim 1 , wherein
Said component a) contains 0 to 4% by weight of vinyl groups and is 1 million mPa.s at 25 ° C. A polyorganosiloxane composition comprising at least one polyorganosiloxane polymer having a viscosity exceeding s. In the polyorganosiloxane composition according to claim 1 or 2 ,
The component b) is silica, alumina, or a mixture of the two, a polyorganosiloxane composition. In the polyorganosiloxane composition as described in any one of Claims 1-3 ,
The component i) comprises at least one kind of aluminum hydroxide treated with an organoalkoxysilane. In the polyorganosiloxane composition as described in any one of Claims 1-4 ,
Said component j), when it is used,
Calcium metasilicate (CaSiO ₃ ) or wollastonite;
Mixed calcium sodium metasilicate (NaCa ₂ HSi ₃ O ₉ ) or sodium calcite; and
Mixed calcium manganese metasilicate [CaMn (SiO ₃ ) ₂ ] or bastamite;
A polyorganosiloxane composition comprising at least one selected from the group consisting of: In the polyorganosiloxane composition as described in any one of Claims 1-5 ,
The optional component f), when used,
At least one anti-structured fl1); and / or
At least one polysiloxane resin f2);
At least one stabilizer f3); and / or
At least one pigment f4); and / or
At least one boron compound f5)
A polyorganosiloxane composition comprising: In the polyorganosiloxane composition as described in any one of Claims 1-6 ,
The polyorganosiloxane composition, wherein the calcined kaolin powder is a chemically surface-treated calcined kaolin powder. Use of a polyorganosiloxane composition according to any one of claims 1 to 7 for the production of one or more single-core wire coverings or primary insulators used to form refractory wires or electrical cables. Because
Use of a polyorganosiloxane composition wherein the composition is deposited around each single conductor and then crosslinked to a silicone elastomer by heating to a material temperature in the range of 100-200 ° C. A fire-resistant electric wire or electric cable produced by the use according to claim 8 of the composition according to any one of claims 1 to 7 . In the electric wire or electric cable according to claim 9 ,
(1) The smoke density is low enough to achieve 80% light transmission according to Part 1 of the standard IEC 61 034,
(2) Complies with standard NFC32-070CR1 under a voltage of 500 volts,
Electric wire or electric cable.